Could CBD prevent COVID-19? Researchers call for clinical trials after promising results

Research from an interdisciplinary group of American researchers suggests that cannabidiol (CBD) inhibits SARS-CoV-2 replication, and could potentially prevent COVID-19. The paper combines results from a large cohort analysis with findings from experiments carried out in human lung cells and in mice. In the cohort analysis, fewer patients taking CBD tested positive for COVID-19 compared to patients not taking CBD. “CBD has anti-inflammatory effects, so we thought that maybe it would stop the second phase of COVID infection involving the immune system, the so-called ‘cytokine storm.’ Surprisingly, it directly inhibited viral replication in lung cells,” said senior author Dr. Marsha Rosner (PhD), a professor in the Ben May department of cancer research at the University of Chicago. Read: 3 years after legalization, we have shockingly little information about how it changed cannabis use and health harms Researchers treated human lung epithelial cells with CBD before exposing them to SARS-CoV-2. When CBD was present above a certain concentration, SARS-CoV-2 could enter the cell but could not replicate. When high concentrations of CBD were present, there was little expression of viral RNA after SARS-CoV-2 was introduced. The effect remained for the alpha, beta and gamma variants of SARS-CoV-2 as well as the wild type. “We just wanted to know if CBD would affect the immune system,” Dr. Rosner said in a press release by the University of Chicago. “No one in their right mind would have ever thought that it blocked viral replication, but that’s what it did.” Further experimentation showed that CBD induces the interferon signalling pathway both directly and indirectly after the host immune response to SARS-CoV-2 infection is activated. When researchers gave CBD to mice who were later infected with SARS-CoV-2, it reduced the SARS-CoV-2 viral load in the lungs and nose in a dose-dependent manner. The mice did not show symptoms of COVID-19 and did not lose weight. Read: Can cannabidiol (CBD) help treat cocaine addiction? In the cohort analysis, researchers analyzed data from 1,212 participants in the National COVID Cohort Collaborative. Significantly fewer patients taking a prescribed oral CBD to treat epilepsy tested positive for COVID-19 (6.2%) compared to patients not taking prescribed CBD (8.9%). The patients in both groups had similar medical conditions and histories. “A clinical trial is necessary to determine whether CBD is really effective at preventing or suppressing SARS-CoV-2 infection, but we think this may have potential as a prophylactic treatment,” said Dr. Rosner. “Maybe you’re in a hot spot or you think you might have been exposed or you’ve just tested positive — that’s where we think CBD might have an effect.” She said that the researchers are keen to see clinical trials launched to study if CBD has anti-viral effects against COVID-19. The researchers stressed that the findings applied only to high concentrations of CBD that had been tested for purity. The CBD used by patients was 100 mg/mL. Other cannabinoids, including cannabidiolic acid (CBDA), cannabidivarin (CBDV) and THC, did not show similar antiviral activity, so the purity of the CBD may be important for it to be effective against SARS-CoV-2. “Going to your corner bakery and buying some CBD muffins or gummy bears probably won’t do anything,” Dr. Rosner said. “The commercially available CBD powder we looked at, which was off the shelf and something you could order online, was sometimes surprisingly of high purity but also of inconsistent quality. It is also hard to get into an oral solution that can be absorbed without the special, FDA-approved formulation.” The study was published in Science Advances on January 20, 2022. Read: More Canadians getting their pot from legal channels than ever before: Health Canada

Could CBD prevent COVID-19? Researchers call for clinical trials after promising results

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